Re: [PATCH v5] cpufreq: qcom: Read voltage LUT and populate OPP

Matthias Kaehlcke
2019-01-23T18:20:59Z

Hi Taniya,

On Wed, Jan 23, 2019 at 04:52:00PM +0530, Taniya Das wrote:
> Add support to read the voltage look up table and populate OPP for all
> corresponding CPUS for consumers like the energy model could use the
> frequency and voltage from the OPP tables. Also update the logic to not add
> duplicate OPPs.
>
> Tested-by: Matthias Kaehlcke <mka@chromium.org>
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> Signed-off-by: Taniya Das <tdas@codeaurora.org>
> ---
> drivers/cpufreq/qcom-cpufreq-hw.c | 46 +++++++++++++++++++++++++++++++--------
> 1 file changed, 37 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
> index d83939a..402ce81 100644
> --- a/drivers/cpufreq/qcom-cpufreq-hw.c
> +++ b/drivers/cpufreq/qcom-cpufreq-hw.c
> @@ -10,18 +10,21 @@
> #include <linux/module.h>
> #include <linux/of_address.h>
> #include <linux/of_platform.h>
> +#include <linux/pm_opp.h>
> #include <linux/slab.h>
>
> #define LUT_MAX_ENTRIES 40U
> #define LUT_SRC GENMASK(31, 30)
> #define LUT_L_VAL GENMASK(7, 0)
> #define LUT_CORE_COUNT GENMASK(18, 16)
> +#define LUT_VOLT GENMASK(11, 0)
> #define LUT_ROW_SIZE 32
> #define CLK_HW_DIV 2
>
> /* Register offsets */
> #define REG_ENABLE 0x0
> -#define REG_LUT_TABLE 0x110
> +#define REG_FREQ_LUT 0x110
> +#define REG_VOLT_LUT 0x114
> #define REG_PERF_STATE 0x920
>
> static unsigned long cpu_hw_rate, xo_rate;
> @@ -70,11 +73,12 @@ static unsigned int qcom_cpufreq_hw_fast_switch(struct cpufreq_policy *policy,
> return policy->freq_table[index].frequency;
> }
>
> -static int qcom_cpufreq_hw_read_lut(struct device *dev,
> +static int qcom_cpufreq_hw_read_lut(struct device *cpu_dev,
> struct cpufreq_policy *policy,
> void __iomem *base)
> {
> u32 data, src, lval, i, core_count, prev_cc = 0, prev_freq = 0, freq;
> + u32 volt;
> unsigned int max_cores = cpumask_weight(policy->cpus);
> struct cpufreq_frequency_table *table;
>
> @@ -83,23 +87,28 @@ static int qcom_cpufreq_hw_read_lut(struct device *dev,
> return -ENOMEM;
>
> for (i = 0; i < LUT_MAX_ENTRIES; i++) {
> - data = readl_relaxed(base + REG_LUT_TABLE + i * LUT_ROW_SIZE);
> + data = readl_relaxed(base + REG_FREQ_LUT +
> + i * LUT_ROW_SIZE);
> src = FIELD_GET(LUT_SRC, data);
> lval = FIELD_GET(LUT_L_VAL, data);
> core_count = FIELD_GET(LUT_CORE_COUNT, data);
>
> + data = readl_relaxed(base + REG_VOLT_LUT +
> + i * LUT_ROW_SIZE);
> + volt = FIELD_GET(LUT_VOLT, data) * 1000;
> +
> if (src)
> freq = xo_rate * lval / 1000;
> else
> freq = cpu_hw_rate / 1000;
>
> - /* Ignore boosts in the middle of the table */
> - if (core_count != max_cores) {
> - table[i].frequency = CPUFREQ_ENTRY_INVALID;
> - } else {
> + if (freq != prev_freq && core_count == max_cores) {
> table[i].frequency = freq;
> - dev_dbg(dev, "index=%d freq=%d, core_count %d\n", i,
> + dev_pm_opp_add(cpu_dev, freq * 1000, volt);
> + dev_dbg(cpu_dev, "index=%d freq=%d, core_count %d\n", i,
> freq, core_count);
> + } else {
> + table[i].frequency = CPUFREQ_ENTRY_INVALID;
> }
>
> /*
> @@ -116,6 +125,7 @@ static int qcom_cpufreq_hw_read_lut(struct device *dev,
> if (prev_cc != max_cores) {
> prev->frequency = prev_freq;
> prev->flags = CPUFREQ_BOOST_FREQ;
> + dev_pm_opp_add(cpu_dev, prev_freq * 1000, volt);
> }
>
> break;
> @@ -127,6 +137,7 @@ static int qcom_cpufreq_hw_read_lut(struct device *dev,
>
> table[i].frequency = CPUFREQ_TABLE_END;
> policy->freq_table = table;
> + dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
>
> return 0;
> }
> @@ -159,10 +170,18 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
> struct device *dev = &global_pdev->dev;
> struct of_phandle_args args;
> struct device_node *cpu_np;
> + struct device *cpu_dev;
> struct resource *res;
> void __iomem *base;
> int ret, index;
>
> + cpu_dev = get_cpu_device(policy->cpu);
> + if (!cpu_dev) {
> + pr_err("%s: failed to get cpu%d device\n", __func__,
> + policy->cpu);
> + return -ENODEV;
> + }
> +
> cpu_np = of_cpu_device_node_get(policy->cpu);
> if (!cpu_np)
> return -EINVAL;
> @@ -199,12 +218,19 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
>
> policy->driver_data = base + REG_PERF_STATE;
>
> - ret = qcom_cpufreq_hw_read_lut(dev, policy, base);
> + ret = qcom_cpufreq_hw_read_lut(cpu_dev, policy, base);
> if (ret) {
> dev_err(dev, "Domain-%d failed to read LUT\n", index);
> goto error;
> }
>
> + ret = dev_pm_opp_get_opp_count(cpu_dev);
> + if (ret <= 0) {
> + dev_err(cpu_dev, "Failed to add OPPs\n");
> + ret = -EINVAL;

nit: in seems -ENODEV would be more correct, it's also what
dev_pm_opp_get_opp_count() would return if the device had no OPP table:
https://elixir.bootlin.com/linux/v4.20.4/source/drivers/opp/core.c#L65

> + goto error;
> + }
> +
> policy->fast_switch_possible = true;
>
> return 0;
> @@ -215,8 +241,10 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
>
> static int qcom_cpufreq_hw_cpu_exit(struct cpufreq_policy *policy)
> {
> + struct device *cpu_dev = get_cpu_device(policy->cpu);
> void __iomem *base = policy->driver_data - REG_PERF_STATE;
>
> + dev_pm_opp_remove_all_dynamic(cpu_dev);
> kfree(policy->freq_table);
> devm_iounmap(&global_pdev->dev, base);

Other than the nit about the return value:

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>

Also re-tested it, so the earlier Tested-by tag is applicable again :)

Thanks

Matthias